So...if she is serving illegally, how are two things handled...first, who physically removes her, and second, is everything she has done (good and bad) null and void? Not being partisan here. Just asking how the law should be handling this. Or is there no means of forcing her to stop "serving"?

I think ptheland's take is probably right. If she's found to not actually hold her office, then actions she took purporting to be holding that office would be void or voidable - but actions of people who properly hold other offices in the U.S. Attorney's office wouldn't necessarily be affected. Maybe. Who knows? It's not like there's a lot of precedent for this kind of thing.

As for physically removing her, I think that "remove" in the context of "removing from office" is literal. No one has to physically take her out of the USA office. The court would simply issue an injunction barring her from taking any actions purporting to be the U.S. Attorney. If she violated that order, she would face penalties. Those penalties might include criminal contempt, I suppose - which might eventually result in someone physically removing her, if a U.S. Marshall comes to arrest her for contempt. But I doubt it would come to that. Once things reach that point, there's literally no point in her trying to exercise the powers of the office, and she'd leave.